Inverse variation can be modeled by the equation:
y = k / x
or
x * y = k
Where k is some constant. If you have one point on the graph, you can plug in x and y and find k and then use it to find other values.
In this case we want to find another point, but we only have one value, so if we find k, then we can go and find the missing x=value
Which would be:
5/4
I hope my answer has come to your help. God bless and have a nice day ahead!